Friday, May 16, 2008

Deep Space Inhabitants - Black Holes

Credit: X-Ray: NASA/CXC/D.Hudson, T.Reiprich et al. (AIfA);
Radio: NRAO/VLA/NRL
The true magnitude of the weirdness of deep space becomes clear when you start to think about things like black holes. Most garden-variety black holes are remnants of supernova explosions that collapse in on themselves. They reach a point of zero volume and infinite density, from which no light can escape.

So how can there be pictures of black holes? It works if you can capture signals other than light. It also helps to target supermassive black holes, which are thought to exist at the centers of some galaxies.

The image above is a composite of x-ray and radio signals and reveals a binary black hole. According to the information on this image, these objects are "surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles."

Composite Image Credit: X-ray in red - NASA/CXC/S.Allen (Kavli Inst., Stanford) et al.;
Radio in blue - NRAO/G.Taylor (VLA);
Infrared in green - NASA/ESA/W.Harris (McMaster Univ.)
Another composite image, this one including infrared, shows material that fell towards a supermassive black hole, then was blasted back out. The blue regions are radio-emitting bubbles that measure about 10,000 light years across.

I like the idea of using different signals to image black holes. When one way of seeing fails, try another. The persistence of astronomers has revealed extraordinary processes where powerful energies swirl around regions of nothingness. These processes allow us to see the cosmic dance of creation and destruction that otherwise would have been hidden by the void of space and of the black holes themselves. Kind of makes me wonder what else we might be missing for fear of the dark...

No comments: